1. Field of the Invention
The present invention relates to an electric drive unit easily mountable to an industrial vehicle such as a forklift truck.
2. Description of the Related Arts
In a battery type industrial vehicle such as a forklift truck, a drive unit including a front axle and an electric motor for traction is mounted to a front part of a vehicle body. For example, Japanese Unexamined Utility Model Publication No. 52-33811 discloses a swingable mount structure in which the electric motor is fixed to the front axle and is swingable about an axis of the front axle shafts.
In such a prior art swingable mount structure, a pair of axle brackets are used for connecting opposite end portions of the front axle to opposite front side frame members of the vehicle body, respectively. Namely, one end of each of the axle brackets swingably secures one end portion of the front axle and the other end of each of the axle brackets is fixed to the front side frame member by four bolts. The electric motor is located behind the front axle and must be further fixed to a front bottom frame member of the vehicle body by an additional securing means including a support bracket, a rubber cushion and bolts, at a central position between the front side frame members.
The assembly work of the above mentioned drive unit is carried out as illustrated in FIG. 4 of the attached drawings. A vehicle body 9 of, for example, a forklift truck is supported while suspended by a hanger 92 of a conveyer rail 91 and a drive unit 8 including a front axle and an electric motor is lifted up under the vehicle body 9 by a lifter on a trolley 98. Then an operator M takes a position under the vehicle body 9 and carries out the assembly work by fitting the opposite end portions of the front axle to the axle brackets connected to the opposite front side frame members, and by fixing the support bracket of the electric motor to the front bottom frame member by bolts.
In the above described assembly work, however, the operator M must work in a bent position with the face upwardly directed while fitting the front axle and fixing the support bracket, as shown in FIG. 4. The operator M must work under great difficulty and is able to use only a restricted physical force when aligning the holes of the support bracket and the front bottom frame member, and tightening the bolts, and thus becomes fatigued in a very short time. As a result, the work efficiency is low.
Also, it is necessary to carry out a periodical inspection of brushes of the electric motor, but the available maintenance space is narrow because a battery charger is often located just behind the electric motor. Also, the entire drive unit must be detached from the vehicle for repair of the electric motor, and thus the maintenance work is difficult.